Oxygen delivery during extreme anemia with ultra-pure earthworm hemoglobin.

Abstract

AIM:

Lumbricus terrestris (earthworm) erythrocruorin (LtEc) is a naturally occurring extracellular hemoglobin (Hb) with high molecular weight (3.6MDa), low autoxidation rate, and limited nitric oxide (NO) dioxygenation activity. These properties make LtEc a potential candidate for use as red blood cell (RBC) substitute, i.e. Hb-based oxygen carrier (HBOC). Previous studies have shown that small amounts of LtEc can be safely transfused into mice, rats, and hamsters without eliciting major side effects. Therefore, this study was designed to understand oxygen (O(2)) transport to tissues and systemic/microvascular hemodynamics induced by LtEc during anemic conditions.

MAIN METHODS:

Hamsters fitted with dorsal window chambers were hemodiluted to 18% hematocrit (Hct) using 6g/dL dextran 70kDa (Dex70). Hemodilution was then continued to 11% Hct using 10g/dL LtEc, 6g/dL Dex70 or 10g/dL human serum albumin (HSA). Blood pressure, heart rate, blood gas parameters, microvascular hemodynamics, microvascular blood flow, functional capillary density (FCD), intravascular pO(2) and perivascular pO(2) were studied.

KEY FINDINGS:

LtEc maintained blood pressure without inducing vasoconstriction while increasing microvascular perfusion and FCD relative to Dex70 and HSA. LtEc increased blood O(2) carrying capacity and maintained systemic and microvascular parameters without decreasing arteriolar diameter or increasing vascular resistance with during extreme anemia. LtEc increased O(2) delivery compared to conventional plasma expanders.

SIGNIFICANCE:

LtEc or synthetic molecules that replicate the characteristics of LtEc could be effective O(2) carriers with potential to be used in transfusion medicine to prevent tissue anoxia resulting from severe anemia.

• Authors: Jacob Elmer, Andre F Palmer, Pedro Cabrales
• Journal: Life sciences (Life Sci) Vol. 91 Issue 17-18 Pg. 852-9 (Oct 29 2012) ISSN: 1879-0631 [Electronic] Netherlands
• PMID: 22982347 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: Copyright © 2012 Elsevier Inc. All rights reserved.

Chemical References

• Blood Substitutes
• Hemoglobins
• Plasma Substitutes
• erythrocruorin
• Oxygen

Topics

• Anemia (blood, drug therapy, metabolism, physiopathology)
• Animals
• Arterial Pressure (drug effects)
• Blood Gas Analysis
• Blood Substitutes (therapeutic use)
• Cricetinae
• Heart Rate (drug effects)
• Hemodilution
• Hemodynamics (drug effects)
• Hemoglobins (isolation & purification, therapeutic use)
• Male
• Microvessels (drug effects, metabolism, physiopathology)
• Oligochaeta (metabolism)
• Oxygen (blood, metabolism)
• Plasma Substitutes (therapeutic use)